Manufacture of curled artificial fibers



' freshly been spun and is still moist.

Patented Oct. 28, 1941 MANUFACTURE T OFFICE No Drawing. Application April 12, 1939, Serial No. 267,520. In Germany April 16, 1938 Claims. (01. 8-129) My present invention relates to a process of curling artificial fibers.

As is known, artificial fibers from cellulose esters or cellulose ethers may be curled by treating the fibers with hot, in particular boiling water, or with hot or boiling aqueous solutions,

'the degree 01' curling depending on the degree to which the fibers undergo swelling. Processes are already known wherein it is intended to-improve the curling effect by adding to the treating baths certain water-soluble substances, especially such agents as enhance the swelling capacity 01' the fibers, for instance acetic acid,

formic acid, alcohol, acetone, di-acetone alcohol,

thiocyanates, salicylates, .anthranilic acid.

My invention has for an object to provide a process for producing a particularly strong, fine- I bowed and permanent curl by using liquids containing water-soluble, low-molecular and nonresinous condensation products from aldehydes, especially formaldehyde, on the one hand, and ammonia or an amine on the other hand. These substances may be added to the liquids either in the form of finished condensationproducts, or

they may also be produced in the liquids thezn- ,selves by addition of both components.

Another object of my invention is to. provide a process for improving the action of the condensation products, especially, that of the cheap and very effective hexamethylenetetramine by adding to the treating baths urea or a low-molecular v substitution product of urea, such as methyl-urea, ethyl-urea or ethylene-urea.

A further, object of the invention is to provide .a process in which such urea derivatives are used as additions as do not impart to the fiber any swelling capacity, at least not, withthe concentrations applied in the present process.

Yet anotherobiect of the invention is the pro-- vision of a process in which such baths are used as contain small amounts of acids, for instance acetic acid or formic acid. Liquids containing both ammonium salts and aldehydes have an acid action from the very beginning.

Other objects of my invention will appear more in detail hereinafter.

The concentration of the effective substance in the treating bath may vary within 'widelimits. A perceptible effect is already produced by means or 1-2 grams of hexamethylenetetramine per liter, especially if the fiber to be treated has The quantity of the substance used will generally amount to 5-25 grams per liter. According to the present process the textile material is preferably material to an action of 15 seconds to 5 minutes,

according to the kindof the material. At any rate, the material should not be treated for such a long time that the effective substances enter into reaction with components of the fiber, thus bringing about a fundamental change in the afilnity of the fiber.

Instead of hexamethylenetetramine there may also be used aldehyde-ammonia (acetic aldehydeammonia), and'water-soluble reaction products from chloral and aminoalcohols, preferably combined with urea.

The proportion by weight of hexamethylenetetramine to urea is advantageously between 1:02 and 1:15, the optimum being about 1:1. The concentration of the chloral-compounds is advantageously 5 to 30 grams per liter. Acids as formic acid may be used in proportion of 1 to 30 grams per liter.

The new process is suitable for treating loose fibers, rayon and spun yarns. Yarns prepared from fibers to which a curl has been imparted in the flake by subjecting the material to boiling. or to another process, may also be treated according to the present invention, the voluminous character, which resembles that of wool, being considerably improved. The process is suitable not only in the case of uniform fibers from cellulose derivatives, especially acetate artificial fibers, but also for purely synthetic fibers from organophilic highly polymerized substances having a certain swelling capacity in Water, such as fibers from polyvinyl-formal or from polyvinylformal acetate. It may, furthermore, be applied in the case of fibers containing components which have a specific influence upon the afllmty of the fiber with respect to dyeing, for instance artificial resins containing basic groups or artificial resins containing either acid groups or both acid andbasic groups.

Iclaim:

1. In a process of curling artificial fibers ol the class consisting of cellulose esters and cellulose ethers, the improvement which comprises treating said fibers with hot aqueous solutions containing water-so uble, low-molecular, nonresinous products obtained by condensing an aldehyde selected from the class consisting of 7 formaldehyde and acetaldehyde with ammonia.

lose ethers, the improvement which comprises treating said fibers with boiling aqueous solutions containing water-soluble, low-molecular,

non-resinous products obtained by condensing an aldehyde selected from the class consisting of formaldehyde and aoetaldehyde with ammonia. j

3. In a process of curling artificial fibers oi the class consisting of cellulose esters and cellulose ethers, the improvement which comprises treating said fibers with hot aqueous-solutions containing water-soluble, low-molecular, nonresinous products obtained by condensing an aldehyde selected from the class consisting of formaldehyde and acetaldehyde with ammonia,

and a'compound selected from the class consisting of urea and a derivative thereof.

4. In a process oi curling artificial fibers. oi the class consisting of cellulose esters and cellulose ethers, the improvement which comprises HERMANNDEILE. 

